Many types of devices can be implemented with reflective-type or projection-type displays, such as mobile phones, portable media players, and the like. Additionally, reflective-type or projection-type display devices can be implemented in a head-mounted display (HMD), such as glasses or other wearable display device that has near-eye display panels as lenses to display an augmented or virtual reality environment. As an emerging technology, there are many challenges and design constraints to developing the optics, imaging units, illumination sources, and display devices small and precise enough for implementation with a wearable display device.
Conventional reflective displays and color-based LCOS (liquid crystal on silicon) projection technologies use color filters to convert white or ambient light to red, green, or blue sub-pixels. However, a majority of the light is lost as it twice passes through the color filters, which can result in an approximately 50-70% loss of the light. The remaining 25-50% of the light that does pass through the color filters is further reduced with polarizers in liquid crystal display-type device, and with reflector imperfections, the overall average is ultimately only about 8-17% of the remaining light before projection optics losses.